The Line of Immortality
by DiscardedNotes
Summary: When a bit of a peculiar deal was struck between a wizard and a demon, no one knew how it would impact the future. Now watch as the changes unfold and a man thoroughly loyal to family does everything in his power to protect those he holds dear. And if in the process he gets to raise his new heir, well who is he to complain?


**A/N: I literally just thought this up while lying down for a moment and decided to write it into a story before I forgot about it. There's a few hints of Supernatural in here in regard to the demons (namely crossroad demons and Crowley in particular) but let it be known I've never watched SPN, only read a few fanfictions. Not to mention the majority of my opinions on demons come from Ao no Exorcist and my OCs within the fandom.**

 **The first part of the story is long before Harry is born (and I do mean centuries before) so it'll be a little while before you find Harry in this chapter. There'll be more of him in the next if I feel like writing it. Not to mention I'd love to put my nose in the things my main OC in this story has been studying, so you betcha there'll be stuff about that showing up. Perhaps chronologically, perhaps not.**

 **Anyways, I've rambled on long enough...**

 **Enjoy!**

* * *

"It's a deal then?" The demon asked, running the stipulations over in his head. Granted they would lose a few souls over time, but the benefits far outweighed the negative aspects really.

"It is." The human replied, nodding his head firmly as if to cement that fact into his own mind. In exchange for immortality as well as that of his heirs (which would be selectively chosen by the magic), the demons would be allowed to claim the souls of those he deemed to have done wrong within his family. Considering human nature, that would be a fair few.

"You know how this works." The demon added, red eyes flashing with amusement as the human had moved to extend his hand, laughing when the man gave a sour look.

"Indeed..."

* * *

"Excuse me dear madam, but would you be so kind as to allow a curious soul a few questions?" When she remained silent he continued. "You see, I'm a genealogist who is currently researching a few lines through the ages. My current project consists of creating a rather large and detailed family tree, including families that married into those lines. Your family is one of those."

The woman looked at him critically before nodding. At least the stronger was dressed well enough and by his robes at least he wasn't a muggle. Being addressed by a muggle would have been disgusting truly, though were he a muggleborn it would be no better. His stature at least proved he had ties with the pureblood history, so she would indulge, just a little.

"Very well. Join me for tea, sir. What is your name, may I ask?" She gestured to the patio just inside the mansion's gates and invited him to sit with her there.

He sat quite contently, digging out a notebook of bound parchment and a quill to take notes. "Thank you madam. You may call me Archonius." He smiled, purposely not disclosing his family name, which he knew would ire her. Then again, should he give his true one, she would not believe him anyway.

"I am Erana." She replied in the same curt manner, not huffing her displeasure simply because her manners would not allow her to do so. "What is it you wish to know?"

"I have been studying your family but the Ministry was being less than helpful as you might imagine, in allowing me to purview the birth records. As such I was wondering if you would be willing to give me a bit more detailed information on your daughter. She had a child, did she not?"

Erana's lips pursed briefly before she acquiesced his statement. "Indeed. Disgraceful girl went and broke contract and her engagement with dear Egrorious, running off with a halfblood who had caught her fancy. Disgusting, it is."

She shook her head and watched him take a few notes and eagerly await the rest of her tale, so she sighed and continued.

"Sorana went and got pregnant, and since it was too late to have the child killed before birth, we opted to remove the blemish afterwards. Filthy halfblood wouldn't stand for it and took the child in by himself, fool that he is."

Archonius carefully noted the information down, equally sketching a short tree from Erana and her husband to Sorana, the unknown halfblood and their child, as well as Egrorius Thorne, her would-be husband.

"You wouldn't happen to know who this particular halfblood is, would you ma'am?" He asked carefully. He'd have to ask the man about what happened from his point of view, as well as note down the child's name when he found out. Keeping track of his family tree could be tiresome but asking questions in the field like this was so much more exciting and interesting!

"No no, I never cared much to know. I cared not to listen once she told me the man was a halfblood." She stated, as though it were obvious and the wise thing to do. Perhaps she thought merely hearing the name would sully her 'pure' blood. Foolish, but then he knew exactly where she would go, once she died.

"Then I thank you kindly for your time ma'am, you've been most helpful. Could you perhaps point me in the direction of your daughter and mister Thorne?" He knew he could track Sorana down himself, but she was skittish with everything that had occurred and was unlikely to be willing to talk to him without her mother's approval.

"She'll be having tea at the Fair Flame later today with her friends, mister Archonius. Good day."

As clear a dismissal as any he thanked her profusely, gathered his papers and made himself scares from the mansion. It was such a sad thing really, to know that over half of his family had found their way into the pits of hell upon death, but then Crowley had been exceedingly pleased with the promotion it had gotten him and both of them knew that this immortality Archonius wielded, was simply the demon's magic keeping his vessel alive through time, bound to the age at which he had made the deal.

He made his way to the town and waited, catching the lady as she excited the high-class shop with her friends, just parting ways. He asked her far fewer questions, such as her intentions for her child and the name of the father, as well as her fiancé's opinion on the whole occurrence.

She was curt, more than a little rude and made it rather obvious that the 'halfblood filth' must have dosed her with amortentia for she would never have slept with him otherwise. The child could die for all she cared and so could the man, Simeon Nott.

The Nott family was relatively new, only just old enough to become its own house and though they cared little about the pureblood doctrine, they too would certainly be caught in its spiel as the purebloods gained power and influence.

Archonius kept searching and addressed the young Nott as well as Egrorius Thorne, asking their opinion as well as asking Nott about the child and how he intended to raise it. Archonius had approved, wondering if the good intentions and new blood would make a difference to the new offspring to his line.

* * *

His evenings were spent buried in a book or working on the family tree, magically expanded, and each new branch settled on a clear sheet of parchment. Alas, only two of his offspring had been chosen to become immortal, their names scripted neatly in gold on the tree.

One he had been unable to reach in time, and had been killed for her inability to age past 25, out of jealousy, out of anger, out of misunderstanding by her own betrothed.

The other had been a son of his line, strong and quickly growing in power none had bothered him about his age and Archonius had had the chance to explain to him, what he was and what opportunities that life brought him.

Understanding, the son had charmed himself to appear his natural age and had lived the double of a normal wizard's life but had eventually taken his own after seeing the death of his loved ones day upon day as he remained the same.

Both losses had hurt him, and in that time none other had come forward to join him his lonely but ever so interesting travels and research. He shouldered on still, noting the birth and deaths of all his family members, their exceptional achievements and which had been sent to Hell or had died naturally, going to Heaven.

When he wasn't tending to his family tree and their destiny, he was studying every book he could get his hands on. He was nearly as obsessed with magic as he was with the demons that had given him this opportunity, and tended to show it quite often.

He was a veritable well of knowledge and very well versed in runes and potions especially, though he enjoyed studying every single branch of magic and how to mix and match to discover new usages for magic. After all, he had all the time in the world!

* * *

"Oh my, this wasn't supposed to happen..." He frowned as he saw the ruins of the cottage in front of him. Hidden from the muggles the fence was covered in messages and flowers and tributes, as well as a few less than savoury symbols, which he removed with a swift flick of his wand.

He had been distracted, so assured that everything would go just fine and that his line would not be targeted directly. Not only that, his line had had a child so their survival was ensured and he often returned to his experiments when that happened. Yet barely a year later, everything went wrong and he hadn't known.

It took him far longer than he'd liked to find the mundane house his child had been abandoned at. So far away from the world he was meant to grow up in, left at the doorstep of a family that had adopted the daughter of his line. But then, Dumbledore hadn't known that, had he?

When he approached the house he saw a small child sitting on the grass attempting to tend to a scraped knee by himself. Next to the boy sat a simple garden adder, hissing at the boy. And of course, to his utter shock, the boy hissed back and he was unable to keep his intrigue to himself.

"My oh my, a parselmouth in the family? How wondrous!" Had he somehow missed something? No, no he couldn't have, so then— Tom Marvolo Riddle, Lord Voldemort, last son of the Gaunt line, the only remaining descendants of old Salazar. Of course, of course it made sense. That scar wasn't there for nothing now was it?

The boy yelped and attempted to get up but slipped and landed on his scraped knee, letting out a small whimper of pain.

"So sorry lad, I didn't mean to startle you." He crouched next to the boy, who looked about five. A bit too young to be his own then, no? How odd... "What's your name?"

"I-I'm Harry... " The boy uttered softly. "Harry Potter."

"I see, Harry." So it was him then, how strange. Had something gone wrong? "Shall I help you with that then Harry? I'm Archonius by the way." He added, swiftly pulling out his wand and tapping it against the boy's knee, which healed instantly.

"N-No, aunt Petunia would get mad—" He gasped when the scrape healed over instantly, looking in wonder and a bit of fear from his knee to the strange man with the long name and back.

"You... You did the M-thing!" He brought out, eyes wide and while Archonius had initially looked rather proud, he soon started frowning. Harry should at least have known of magic, should he not? He was at the age he would have performed accidental magic multiple times already...

"Of course I did Harry. I'm a wizard just like you, someone who can do magic."

Harry looked frightened then, looking around as though his aunt or uncle would materialise out of thin air to punish him and the strange man.

"No! Aunt Petunia and uncle Vernon say that... That magic isn't real." He all but whispered the forbidden word, leaning forward so he could say it as softly as possible. Speaking of magic was forbidden to the point Dudley wasn't allowed to watch cartoons with magic in them.

Surely they must have known Harry was a wizard? Lily was a witch after all and her adoptive family would have read the letter and sent her off to Hogwarts. Her sister would have known as well... So then, why didn't they tell the lad?

A bad feeling began to settle in Archonius' gut as he looked between Harry and the house, where a horse-faced woman that might very well have been the young Petunia he had once seen was bustling around the kitchen, apparently grabbing cake for her son.

"I'm afraid they've been less than truthful with you then, my dear boy... Magic is real and once you turn eleven, you 'll be old enough to attend a school for magic. You'll get a letter and all explaining it." Another glance at the house had Petunia looking around as though searching for someone, oh dear...

"It looks like I'll have to leave for a little while now Harry. I've overlooked much it seems and I'll have to make inquiries, but you will see me again. That I promise you."

And in a sharp crack he disappeared from number 4, Privet Drive, Surrey not to be seen for the next four years until Harry Potter turned eleven.


End file.
